Does LibreSSL 2.4.0 support the Nginx dual certificate option?
As it does not work with version LibreSSL < 2.40.

Only OpenSSL 1.0.2 and higher support separate chains for
different certificates. With older versions (including LibreSSL)
there is only one chain for all certificates, and all chained
certificates will be added to it. That is, if chains are the same
you have to leave only one of them.